Apparatus for dispensing a plurality of powders and method of compounding substances

ABSTRACT

An apparatus for dispensing a plurality of powders or flowable materials, such as colorants for paint, caulking or grout or components of cosmetics, comprising a plurality of containers for holding the powders or flowable materials, a plurality of metering pumps, connected to a container or having a connector for releasably connecting a container to the respective pump, wherein the capacity of the metering pump is selectable.

BACKGROUND

1. Technical Field

The invention relates to an apparatus for dispensing a plurality ofpowders, such as colorants for paint, dye, caulking or grout orcomponents of cosmetics, and to a method of compounding substances.

2. Background of the Related Art

A prior art apparatus of this type is disclosed in U.S. patentapplication 2003/0230355. This document pertains to an interactivecosmetic body powder selection system having a point of sale dispenser.The system includes a cosmetic powder dispenser that contains aplurality of different shades, tints or hues of colors or pigments,which can be dispensed in pre-selected proportions to create a customcolor selection. A user-interactive system is provided at apoint-of-sale for allowing a user to choose or dispense a color, effect,or both. Information about the selection is employed for dispensing theappropriate proportions of ingredients. Preferably the ingredients aredispensed manually into a powder canister having an integrated brush influid communication with the canister. In another embodiment, the systemis automated.

U.S. Pat. No. 4,959,947 relates to an apparatus for the production andpackaging of a compound mixture, in which extremely accurate and rapidweighing-out, proportioning and packaging of individual components areachieved, is provided. For this, filling stations (4 to 6) are equippedwith combined discharge, weighing and transfer devices (22), which allowsingle-component treatment. In column 4, lines 25 to 32 it is statedthat “The first type of filling station 4 (individual vessels 1 to 4)illustrated in FIG. 1 has a discharge device 23 which is composed of twoelectronically controlled worm conveyors 24 arranged above one anotherand of an electronically controlled shutoff valve 25. The double wormconveyor serves for matching the proportioning capacity to the materialto be conveyed or to the amount to be weighed out from the feed vessel7.”

German Utility Model 299 24 013 relates to a metering device for apowder, such as aluminum powder for making cellular concrete, whichcomprises a relatively large screw for generating a relatively largemass flow and a relatively small screw, which receives material from therelatively large screw.

An aspect of the present invention provides an apparatus for and methodof relatively accurately and relatively quickly dispensing differentamounts of powder.

In accordance with a further aspect of the invention, the said amountsvary over a wide range.

A still further aspect of the invention provides an apparatus ofrelatively robust construction.

SUMMARY OF THE DISCLOSURE

The invention relates to an apparatus for dispensing a plurality ofpowders, such as colorants for paint, caulking-or grout or components ofcosmetics, comprising a plurality of containers for holding the powders,a plurality of metering powder pumps, connected to a container or havinga connector for releasably connecting a container to the respectivepowder pump, wherein the capacity of the metering powder pump, i.e. theamount dispensed at each revolution (in case of screw pumps) or nominalstroke (in case of a piston pumps) is selectable.

By employing metering pumps of which the capacity is selectable, thetime needed for dispensing a particular amount of powder can be reducedand/or the accuracy with which this amount is dispensed can beincreased. In other words, it becomes possible to optimize for speed onthe one hand and accuracy on the other.

A selectable capacity can be achieved in various ways. E.g. by providinga screw pump, which can be tilted so as to lower the outlet opening andthus stimulate the flow of powder, or by providing a screw pump, whereinthe screw comprises a helical wire or spring wound about a rod andwherein the effective pitch of the screw and thus the capacity can beincreased respectively decreased by elongating respectively shorteningthe helical wire or spring. It is also possible to employ a conicalscrew housed in a (horizontal) conical chamber, with the outlet openingat the apex of the conical chamber. By moving the screw, in axialdirection, away from or towards the outlet opening, the capacity of thepowder pump can be respectively increased or decreased.

However, it is preferred that the metering powder pumps comprise atleast two, preferably separated pump mechanisms, one mechanism having arelatively large dispensing capacity and another mechanism having arelatively small dispensing capacity. With such pumps, the amounts to bedispensed may vary over a wide range.

It is further preferred that the apparatus according to the inventioncomprises at least one weighing device for weighing at least one,preferably all of the dispensed amounts.

The invention further relates to a method of compounding substances,such as paints, dyes, caulking or grout or cosmetics, comprising thesteps of

-   -   providing apparatus comprising a plurality of containers holding        powders, a plurality of metering powder pumps,    -   dispensing an amount of powder into a receptacle by means of at        least one of the metering powder pumps and    -   selecting the capacity of this metering powder pump prior to or        during the dispensing of that amount.

It is preferred that at least some, preferably all of the meteringpowder pumps comprise at least two pump mechanisms and that the methodfurther comprises the steps of

-   -   dispensing a relatively large part of the said amount by means        of one mechanism and    -   dispensing a relatively small part of the said amount by means        of another mechanism.

Optimization of speed and/or accuracy is further facilitated if the saidlarge part is at least ten times larger than the said small part.

The method according to the present invention is especially suitable forcompounding substances at a point-of-sale or, in case of paint, at apaint shop.

Within the framework of the invention, the term “powder” is defined asparticles having a size in a range from 0 to 1500 μm, preferably in arange from 10 to 500 μm, and at least includes granulates,microgranulates, crystals, frit, grounds, microspheres and the like.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an apparatus for dispensing powders;

FIG. 2 is a perspective top view of a metering pump used in theapparatus of FIG. 1;

FIG. 3 is a further top view of the said metering pump;

FIGS. 4 and 5 are cross-sectional side views of a container and meteringpump used in the apparatus of FIG. 1.

It is noted that the drawings are not necessarily to scale and thatdetails, which are not necessary for understanding the presentinvention, may have been omitted. The terms “upper”, “lower”,“horizontal”, “vertical”, “front”, “rear”, and the like relate to theembodiments as oriented in the figures. Further, elements that are atleast substantially identical or that perform an at least substantiallyidentical function are denoted by the same numeral.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

FIGS. 1 and 2 illustrate an example of an apparatus 1 for dispensing aplurality of powders, such as pigments for compounding paints, dyes,caulking or grout or components of cosmetics, e.g. foundations. It canbe used for numerous paint or cosmetic recipes and can be located e.g.at a retailer, a spa or at a body repair shop for cars.

This particular dispensing apparatus 1 is an automated version andincludes a horizontal turntable 2, mounted on a support 3 and carrying,along its circumference, a plurality of metering powder pumps 4 andtwenty-four containers 5 for the powders. The turntable 2 can be rotatedabout a vertical, central axis by means of a motor inside the support 3and between discrete positions, in this case forty-eight positions (twofor each container as will become apparent below) including a front ordispensing position provided with a stepper motor 6 for driving one ofthe pumps 4.

The apparatus 1 further comprises a control device 7 comprising a smallkeyboard 8 for entering information, such as client data and paintrecipes, and a display 9. The control device 7 also comprises a computer10 for storing the said information and for driving the turntable 2 andthe stepper motor 6.

A weighing device 11, comprising an upper plate (shown in FIG. 1) onwhich a cup or other receptacle can be placed and a load-cell (hiddenfrom view and known in itself), is located beneath the pump 4 and thecontainer 5 that are in the dispensing position. Optionally, a dispenser(not shown) for cups or other receptacles can be provided, especiallywhen the apparatus 1 is being employed for dispensing components ofcosmetics.

As can be seen in FIGS. 2 and 3, each of the metering pumps 4 comprisesa housing 12 having a inlet chamber 13, with an inlet opening facingupwards and positioned beneath a container 5, and a polycylindrical bore(shown in cross-section in FIGS. 4 and 5) leading to an outlet chamber14 facing downwards and, during dispensing, positioned over a receptacle15. A lid 16 is pivotably mounted on the housing 11 for closing theoutlet chamber 14.

Inserts 17 are mounted, e.g. by means of an external screw thread, inthe said channel. These inserts 17 are provided with axially extendingpump chambers, which accommodate two concave profile screws 18 ofdifferent size and which can be readily replaced, e.g. when a differenttype or size of screw is to be fitted.

In this example, the screws 18 extend radially with respect to theturntable 2. The relatively large screw 18A has a diameter of 22 mm anda double pitch of 12 mm, yielding a dispensed volume for each revolutionof 735 mm³, whereas the relatively small screw 18B has a diameter of 8.5mm and a double pitch of 7 mm, yielding a dispensed volume for eachrevolution of 35 mm³. First ends of the screws 18, extending away fromthe central vertical axis of the turntable 2, are each provided with anadaptor 19 which is to be engaged by the stepper motor 6, as will beexplained in more detail below. Further, each of the screws 18 is madeof polypropylene (PP) or Teflon™ (PTFE) reinforced with a cylindricalmetal rod 20.

In order to further improve the dispensing accuracy of the screws 18,the effective outer diameter of the screws 18 is in excess of theeffective inner diameter the respective chamber. The rim of the screw isat least partially bent in the displacement direction of the pump. Suchbending can be achieved by simply inserting the oversized screws in thechannels from the outlet side towards in the inlet side.

In an alternative embodiment, which is especially suitable for fragilepowders, the effective outer diameter of the screw is smaller than theeffective inner diameter of the respective chamber, resulting inclearance between the screw and the chamber, and wherein the screw isprovided with bristles that bridge this clearance. This type of screwwas found to be effective in reducing the forces exerted on the powder.

As illustrated in FIGS. 4 and 5, during the dispensing of a particularrecipe, e.g. consisting just of powders to be dispensed and mixed in acup or consisting of a base material into which one or more powdersshould be dispensed, the turntable 2 is rotated about its vertical axisuntil the container 5 with the required powder is in the dispensingposition. Subsequently, the lid 16 is opened and, depending on theamount to be dispensed, the large screw 18A, which a particular powderhaving a density of, say, 0.57 g/cm³ dispenses 0.42 g for eachrevolution, or the small screw 18B, which dispenses 20 mg for eachrevolution, is selected. E.g. if 84, 36 g is to be dispensed, the largescrew 18A is positioned in front of the stepper motor 6, engaged by thesame, and driven to completed 200 turns. Subsequently, the small screw18B is positioned in front of the stepper motor 6, engaged by the same,and driven to complete 18 turns, yielding the required amount.

In another example, employing the weighing device 11, if the screws havean accuracy of 2%, 96% of the required amount is dispensed by the largescrew 18A and the dispensed amount is verified by the weighing device11. If it is established that e.g. 97% of the required amount has beendispensed, the large screw 18A is driven to dispense a total of 99% andthe remaining part is dispensed by means of the small screw 18B.

The accuracy of the screws can be further enhanced by calibrating,relative to a reference or zero position of the screw, the dispensedamounted in several positions within one revolution, e.g. for each stepof 30 degrees yielding a total of 12 steps in one revolution. Bycalibrating for several positions, any non-linear effects can be takeninto account. These effects dependent inter alia on the dimensions andmaterial of the screw and on the powder that is being dispensed. In somecases, the screw will dispense relatively small amounts or not dispenseat all during e.g. two or three steps and then dispense a relativelylarge amount in the fourth step, which phenomenon could be referred toas “pulsing”. Many of these effects were found to be sufficientlyregular to allow compensation by calibration.

In addition to use during dispensing, the above-described weighingdevice 11 can also be used to calibrate one or more of the pumps.

Once dispensing of a particular powder has been completed, the lid 16 isclosed and the turntable 2 is rotated until the next required container5 is in the dispensing position. Closing the lid 16 prevents powder fromfalling out during rotation. In an alternative embodiment, the screwsthat have just been used are revolved in reverse direction prior torotation of the turntable thus drawing the powder back into the meteringpowder pump.

With the above described apparatus and method dispensing it is possibleto relatively accurately and quickly dispense amounts ranging from e.g.10 milligram to 500 gram.

As a matter of course, this disclosure is not restricted to theabove-disclosed embodiments, which may be varied in different mannerswithin the spirit and scope of the invention. For example, the apparatusaccording to the present invention can be configured as a lineardispensing apparatus i.e. with the containers aligned is a row. Also,the apparatus may comprise at least one container for a liquid and ametering liquid pump connected to that container.

1. An apparatus for dispensing a plurality of flowable materialcomprising: a plurality of containers for holding the materials, aplurality of pumps, connected to a container or having a connector forreleasably connecting a container to the respective pump, wherein thecapacity of the pump is selectable.
 2. The apparatus of claim 1, whereinat least some, preferably all of the pumps comprise at least two pumpmechanisms, one mechanism having a relatively large dispensing capacityand another mechanism having a relatively small dispensing capacity. 3.The apparatus of claim 2, wherein at least one of the pump mechanismscomprises a pump screw accommodated in a pump chamber.
 4. The apparatusof claim 3, wherein the effective outer diameter of the screw is inexcess of the effective inner diameter the respective chamber andwherein the rim of the screw is at least partially bent in thedisplacement direction of the pump.
 5. The apparatus of to claim 3,wherein the effective outer diameter of the screw is smaller than theeffective inner diameter of the respective chamber, resulting inclearance between the screw and chamber, and wherein the screw isprovided with bristles that bridge this clearance.
 6. The apparatus ofclaim 2, which comprises a dispensing position common to all meteringpumps and wherein a driver for engaging the pump mechanisms is locatedat the dispensing position.
 7. The apparatus of claim 6, wherein thedriver comprises a stepper motor.
 8. The apparatus of claim 1, which isarranged to dispensing any amount in a range from 10 Mg to 500 g.
 9. Theapparatus according to claim 1, comprising at least one weighing devicefor weighing at least one of the dispensed amounts.
 10. The apparatusaccording to claim 1, which further comprises at least one container fora liquid and a metering liquid pump connected to that container.
 11. Theapparatus according to claim 3, wherein the screw or screws are made ofa polyolefin, preferably PP or. PTFE.
 12. A method of compoundingsubstances comprising: providing an apparatus comprising a plurality ofcontainers holding flowable materials, a plurality of metering pumps,each metering pump being driven by a stepper motor, dispensing an amountof one of the materials into a receptacle by means of at least one ofthe metering pumps and the stepper motor, weighing the dispensed amount,comparing the dispensed amount with predetermined desired amount, andusing a difference between the dispensed amount and the desired amountto adjust operation of the at least one metering pump and the steppermotor during future dispenses.
 13. The method of claim 12, wherein atleast some, preferably all of the metering pumps comprise at least twopump mechanisms and which further comprises: dispensing a relativelylarge part of the said amount by means of one mechanism and dispensing arelatively small part of the said amount by means of another mechanism.14. The method of claim 13, wherein the said large part is at least tentimes larger than the said small part.
 15. The method of claim 12,wherein the weight of each of the dye components is measuredindividually.
 16. The method of claim 12, wherein at least one materialis dispensed in a base material, such as a base paint.
 17. The method ofclaim 12, wherein the substances are compounded at a point-of-sale. 18.The method of claim 12, further comprising selecting the capacity ofthis metering powder pump prior to or during the dispensing of thatamount.
 19. The apparatus of claim 9, wherein the weighing device andmetering pumps are linked to a controller and wherein each time aparticular pump dispenses an amount, the weighing device weighs thedispensed amount and the controller compares the dispensed amount with apredetermined desired amount and uses any difference between thedispensed and desired amounts to modify a number of steps of the steppermotor during future dispenses.
 20. A method of dispensing a plurality offlowable cosmetics ingredients utilizing individually controlleddispense pumps drawing flowable material from separate containers, thepumps positioned to dispense to a common receptacle with a weighingdevice associated with the receptacle and a computer controllingoperation of the pumps, the method comprising: operating a selected pumpin a controlled manner to move a predetermined assumed amount of achosen flowable material less than a desired complete dispense amount ofsaid material to said receptacle in accordance with a program stored onsaid computer which relates a parameter of pump operation to thepredetermined assumed amount of flowable material, weighing an amountactually dispensed to said receptacle and determining an actual amountdispensed, comparing the actual amount dispensed to the predeterminedassumed amount and determining a difference between the actual amountdispensed and the predetermined assumed amount to provide a deviationdetermination between the predetermined assumed amount and actualdispensed amount for the selected pump, utilizing said deviationdetermination as a modifier to the parameter for further dispensethrough controlled operation of the selected pump.
 21. The method ofclaim 20 wherein the parameter is a number of steps carried out by thestepper motor to dispense a unit weight of flowable material from theselected pump.
 22. A method of compounding substances comprising:providing an apparatus comprising a plurality of containers holdingflowable materials, and a plurality of metering pumps, each meteringpump being linked to two orifices of different sizes including a largeorifice and a small orifice, dispensing an amount of one of thematerials into a receptacle by means of at least one of the meteringpumps through the large orifice, weighing the dispensed amount,comparing the dispensed amount with predetermined desired amount, usinga difference between the dispensed amount and the desired amount tocalculate new amount to be dispensed and operating to dispense the newamount through the small orifice.
 23. The method of claim 22 whereineach pump comprises two pump elements including a small pump element anda large pump element with the small orifice accommodating the small pumpelement and the large orifice accommodating the large pump element.